1. Field
The present invention relates to a wireless communication system, and more particularly to a method and an apparatus for aperiodically transmitting and receiving a control signal for estimating a channel state of a resource in a wireless communication system.
2. Discussion of the Background
With the progress of communication systems, consumers such as companies and individuals have used a wide variety of wireless terminals.
In current wireless communication systems such as a 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) and a 3GPP LTE-A (LTE Advanced), as a high-speed and high-capacity communication system capable of transmitting and receiving various data such as images and wireless data beyond voice-oriented services, it is required to develop a technology capable of transmitting a large amount of data coming close to that of a wired communication network. In addition, an appropriate error correction and detection scheme in which system performance can be improved by minimizing information loss and increasing system transmission efficiency, becomes an essential element.
Also, in current wireless communication systems, various control signals are used to provide information on a communication environment and the like to a counterpart apparatus in uplink or downlink. As an example of control signals, a reference signal is being discussed.
For example, in an LTE (Long Term Evolution) system, during uplink transmission, a user equipment (UE) transmits a sounding reference signal corresponding to a channel estimation reference signal indicating a channel state, to a base station. Meanwhile, during downlink transmission, in order to detect channel information, the base station transmits a Cell-specific Reference Signal (CRS) corresponding to a reference signal to the UE in each subframe.
Also, recently, due to the flexibility and the like of a communication system, a discussion intended to aperiodically transmit a channel estimation reference signal and the like is in progress. However, a current state is that a specific scheme and the like related to this discussion have not been determined. In view of these conditions, there is a need for a specific method for transmitting an aperiodic channel estimation reference signal.